Palladium and half sandwich ruthenium(II) complexes of selenated and tellurated benzotriazoles: Synthesis, structural aspects and catalytic applications

1-(Phenylselenomethyl)-1H-benzotriazole (L-1) and 1-(4-methoxyphenyltelluromethyl)-1H-benzotriazole (L-2) have been synthesized by reacting 1-(chloromethyl)-1H-benzotriazole with in situ generated nucleophiles PhSe and ArTe, respectively. The complexes of L-1 and L-2 with Pd(II) and Ru(II)(eta(6)-p-cymene) have been synthesized. Proton, carbon-13, Se-77 and/or Te-125 NMR spectra authenticate both the ligands and their complexes. The single crystal structures of L-1, L-2 and [RuCl(eta(6)-p-cymene)(L)][PF6] (L = L-1: 3, L = L-2: 4) have been solved. The Ru-Se and Ru-Te bond lengths have been found 2.4801(11) and 2.6183(10) angstrom, respectively. The palladium complexes, [PdCl2(L)] (L = L-1: 1, L = L-2: 2) have been explored for Heck and Suzuki-Miyaura C-C coupling reactions. The TON values are upto 95,000. The Ru-complexes have been found promising for catalytic oxidation of alcohols (TON similar to 7.8-9.4 x 10(4)). The complexes of telluroether ligands are as efficient catalysts as those of selenoether ones and in fact better for catalytic oxidation. (C) 2009 Elsevier B. V. All rights reserved.